Note: * When the load current is higher than 10A, a heat sink must be added to the SSR or the SSR should be mounted on a metal base plate with heat dissipation effect, and apply the thermal grease between them. When the load current is higher than is 40A or more, fan forced cooling or water cooling is needed.* Heat sink is Not included.

Solid State Relay Dimension

3 Phase SSR Wiring Diagram

Tips: How to use solid state relays in three-phase current control?

The easiest way is to use two solid state relays for motor’s on-off control, four for commutation control, and the third phase is not controlled. For a motor, it should be noted that, due to motor inertia, its commutation must be conducted after it comes to a standstill in case of similar motor stalling, which may cause a great impact voltage and current. In the design of the control circuit, pay attention to the possibility that the commutating solid state relay is turned on, and it is forbidden at any moment. As for power sequence, power supply of control circuit should be turned off later if added first while the power supply of electrical machinery should be turned off first if added later. Inverters should not be simply adopted to connect commutating SSRs in case of phase fault caused by the phenomenon that the turned-on solid state relay has not been turned off yet while another phase of SSR is already turned on. In addition, fuses, phase loss and temperature relays involved in the motor control are also protection devices to ensure normal operation of the system.